When a peroxyacid bleach is dissolved or released into a laundry wash solution bleaching begins. Controlled release of the peroxyacid bleach is important in various laundering systems.
DELAYED BLEACH RELEASE: Delayed release of peroxyacid into a wash solution is advantageous when certain bleach incompatible components are in the laundering system. For example, the use of enzymatic material for specific removal of stains on which peroxyacid bleaches are deficient make the formulation of laundry systems comprising a peroxyacid bleach and enzymes desirable. However, since enzymes and bleach are incompatible, the delayed release or dissolution of the bleach into the solution are the rapid release of the enzyme into the wash solution is desirable. Such a system provides both improved enzyme and bleach performance as compared to a system in which both are released into the wash solution at the same time. PA0 RAPID BLEACH RELEASE: While delayed bleach release is desirable in some laundering systems, it is undesirable in others; specifically, when the rapid release of all of the bleach is desirable for maximum peroxyacid bleaching; for example, in a laundering system which does not contain enzymatic material. PA0 PUBLISHED REFERENCES: The following references will serve as background art for the present invention. PA0 OBJECTS: An object of the present invention is to provide a controlled release laundry bleach product which does not require a coated bag. PA0 I. a peroxyacid bleach selected from the group consisting of hydrotropic and hydrophilic peroxyacid bleaches, e.g., diperoxydodecanedioic acid (DPDA); PA0 II. an effective amount of a bleach release-delaying agent; e.g., sodium laurate at a level of at least 10% by weight of the DPDA;
European Patent Application No. 18,678, published Nov. 12, 1980, Tan Tai Ho, discloses a bleach product comprising a percompound contained within a bag of fibrous material. The bag is coated with a protective water-permeable coating which is removable in 30.degree.-75.degree. C. water.
Example V of the Ho EPO Patent Application discloses a coated bagged powder "diperisophthalic acid including a stabilizer (sic)." Ho reports in Example V that "the detrimental effect of diperisophthalic acid upon enzymes is delayed, and therefore improvement in enzymatic efficiency is obtained."
Other useful background art is listed below.
______________________________________ Inventor Issue Date ______________________________________ Canadian Pat. No. 635,620 McCune 1/30/62 U.S. Pat. No. 3,414,593 Robson 12/3/68 4,017,411 Diehl et al. 4/12/77 4,100,095 Hutchins 7/11/78 4,126,573 Johnston 11/21/78 ______________________________________
Other objects of the present invention will be apparent in the light of the following disclosure.